Answer:
The entropy change of the sample of water = 6.059 x 10³ J/K.mol
Explanation:
Entropy: Entropy can be defined as the measure of the degree of disorder or randomness of a substance. The S.I unit of Entropy is J/K.mol
Mathematically, entropy is expressed as
ΔS = ΔH/T....................... Equation 1
Where ΔH = heat absorbed or evolved, T = absolute temperature.
<em>Given: If 1 mole of water = 0.0018 kg,</em>
<em>ΔH = latent heat × mass = 2.26 x 10⁶ × 1 = 2.26x 10⁶ J.</em>
<em>T = 100 °C = (100+273) K = 373 K.</em>
<em>Substituting these values into equation 1,</em>
<em>ΔS =2.26x 10⁶/373</em>
ΔS = 6.059 x 10³ J/K.mol
Therefore the entropy change of the sample of water = 6.059 x 10³ J/K.mol
Answer:
0.031 W
Explanation:
The power used is equal to the rate of work done:
where
P is the power
W is the work done
t is the time taken to do the work W
In this problem, we have:
W = 900 J is the work done by the motor
t = 8 h is the time taken
We have to convert the time into SI units; keeping in mind that
1 hour = 3600 s
We have
And therefore, the power used is
Answer:
The critical radius of the plastic insulation is 0.72 inches.
Explanation:
Given that,
Diameter = 0.091 in
Thickness = 0.02 in
Initial temperature = 90°F
Final temperature = 50°F
Heat transfer coefficient = 2.5 Btu/h.ft²°F
Material conductivity = 0.075 Btu/h.ft °F
We need to calculate the critical radius of the plastic insulation
Using formula of critical radius
Where, k = Material conductivity
h = Heat transfer coefficient
Put the value into the formula
Hence, The critical radius of the plastic insulation is 0.72 inches.
Answer:
a) 376 m
b) 21.5 s
c) -13.9 m/s
d) 3.08 s, 39.9 s
Explanation:
Given:
y₀ = 0 m
v₀ = 35 m/s
a = -1.63 m/s²
a) Find: y when v = 0 m/s.
v² = v₀² + 2a (y − y₀)
(0 m/s)² = (35 m/s)² + 2(-1.63 m/s²) (y − 0 m)
y = 376 m
b) Find: t when v = 0 m/s.
v = at + v₀
0 m/s = (-1.63 m/s²) t + 35 m/s
t = 21.5 s
c) Find: v when t = 30 s.
v = at + v₀
v = (-1.63 m/s²) (30 s) + 35 m/s
v = -13.9 m/s
d) Find: t when y = 100 m.
y = y₀ + v₀ t + ½ at²
100 m = 0 m + (35 m/s) t + ½ (-1.63 m/s²) t²
100 = 35t − 0.815 t²
Solve with quadratic formula:
t = 3.08 s, 39.9 s
Answer:
4.8 A
Explanation:
Voltage = current x resistance
(V = IR)
12 = I (0.5 +2)
I = 4.8 A
